bitmap.h

上一个上传的有问题,这个是好的。visopsys包括系统内核和GUI的全部SOURCE code ,还包括一些基本的docs文档。里面src子目录对应所有SOURCE code.对于想研究操作系统的朋

/*
 * bitmap.h - Exports for bitmap handling. Part of the Linux-NTFS project.
 *
 * Copyright (c) 2000-2004 Anton Altaparmakov
 * Copyright (c) 2004-2005 Richard Russon
 *
 * This program/include file is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as published
 * by the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program/include file is distributed in the hope that it will be
 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program (in the main directory of the Linux-NTFS
 * distribution in the file COPYING); if not, write to the Free Software
 * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#ifndef _NTFS_BITMAP_H
#define _NTFS_BITMAP_H

#include "types.h"
#include "attrib.h"

/*
 * NOTES:
 *
 * - Operations are 8-bit only to ensure the functions work both on little
 *   and big endian machines! So don't make them 32-bit ops!
 * - bitmap starts at bit = 0 and ends at bit = bitmap size - 1.
 * - _Caller_ has to make sure that the bit to operate on is less than the
 *   size of the bitmap.
 */

/**
 * ntfs_bit_set - set a bit in a field of bits
 * @bitmap:	field of bits
 * @bit:	bit to set
 * @new_value:	value to set bit to (0 or 1)
 *
 * Set the bit @bit in the @bitmap to @new_value. Ignore all errors.
 */
static __inline__ void ntfs_bit_set(u8 *bitmap, const u64 bit,
		const u8 new_value)
{
	if (!bitmap || new_value > 1)
		return;
	if (!new_value)
		bitmap[bit >> 3] &= ~(1 << (bit & 7));
	else
		bitmap[bit >> 3] |= (1 << (bit & 7));
}

/**
 * ntfs_bit_get - get value of a bit in a field of bits
 * @bitmap:	field of bits
 * @bit:	bit to get
 *
 * Get and return the value of the bit @bit in @bitmap (0 or 1).
 * Return -1 on error.
 */
static __inline__ char ntfs_bit_get(const u8 *bitmap, const u64 bit)
{
	if (!bitmap)
		return -1;
	return (bitmap[bit >> 3] >> (bit & 7)) & 1;
}

static __inline__ void ntfs_bit_change(u8 *bitmap, const u64 bit)
{
	if (!bitmap)
		return;
	bitmap[bit >> 3] ^= 1 << (bit & 7);
}

/**
 * ntfs_bit_get_and_set - get value of a bit in a field of bits and set it
 * @bitmap:	field of bits
 * @bit:	bit to get/set
 * @new_value:	value to set bit to (0 or 1)
 *
 * Return the value of the bit @bit and set it to @new_value (0 or 1).
 * Return -1 on error.
 */
static __inline__ char ntfs_bit_get_and_set(u8 *bitmap, const u64 bit,
		const u8 new_value)
{
	register u8 old_bit, shift;

	if (!bitmap || new_value > 1)
		return -1;
	shift = bit & 7;
	old_bit = (bitmap[bit >> 3] >> shift) & 1;
	if (new_value != old_bit)
		bitmap[bit >> 3] ^= 1 << shift;
	return old_bit;
}

extern int ntfs_bitmap_set_run(ntfs_attr *na, s64 start_bit, s64 count);
extern int ntfs_bitmap_clear_run(ntfs_attr *na, s64 start_bit, s64 count);

/**
 * ntfs_bitmap_set_bit - set a bit in a bitmap
 * @na:		attribute containing the bitmap
 * @bit:	bit to set
 *
 * Set the @bit in the bitmap described by the attribute @na.
 *
 * On success return 0 and on error return -1 with errno set to the error code.
 */
static __inline__ int ntfs_bitmap_set_bit(ntfs_attr *na, s64 bit)
{
	return ntfs_bitmap_set_run(na, bit, 1);
}

/**
 * ntfs_bitmap_clear_bit - clear a bit in a bitmap
 * @na:		attribute containing the bitmap
 * @bit:	bit to clear
 *
 * Clear @bit in the bitmap described by the attribute @na.
 *
 * On success return 0 and on error return -1 with errno set to the error code.
 */
static __inline__ int ntfs_bitmap_clear_bit(ntfs_attr *na, s64 bit)
{
	return ntfs_bitmap_clear_run(na, bit, 1);
}


#ifdef NTFS_RICH

#include "layout.h"
#include "inode.h"

/**
 * struct ntfs_bmp -
 *
 * a cache for either dir/$BITMAP, $MFT/$BITMAP or $Bitmap/$DATA
 */
struct ntfs_bmp {
	ntfs_volume	 *vol;
	ntfs_attr	 *attr;
	int		  count;
	u8		**data;
	VCN		 *data_vcn;
};


int ntfs_bmp_rollback(struct ntfs_bmp *bmp);
int ntfs_bmp_commit(struct ntfs_bmp *bmp);
void ntfs_bmp_free(struct ntfs_bmp *bmp);
struct ntfs_bmp * ntfs_bmp_create(ntfs_inode *inode, ATTR_TYPES type, ntfschar *name, int name_len);
int ntfs_bmp_add_data(struct ntfs_bmp *bmp, VCN vcn, u8 *data);
u8 * ntfs_bmp_get_data(struct ntfs_bmp *bmp, VCN vcn);
int ntfs_bmp_set_range(struct ntfs_bmp *bmp, VCN vcn, s64 length, int value);
s64 ntfs_bmp_find_last_set(struct ntfs_bmp *bmp);
int ntfs_bmp_find_space(struct ntfs_bmp *bmp, LCN start, long size);

#endif /* NTFS_RICH */

#endif /* defined _NTFS_BITMAP_H */